Updated

A U.S. diplomat said Tuesday that envoys from the five permanent Security Council members plus Germany discussed sanctions against Iran over its nuclear program, but failed to agree on how to proceed.

Undersecretary of State Nicholas Burns told The Associated Press after nearly three hours of talks that diplomats recognized the "need for a stiff response to Iran's flagrant violations of its international responsibilities."

He said the possibility of sanctions was discussed during the meeting hosted by the Russian Foreign Ministry, but indicated that further talks would be needed.

"Iran's actions last week provoked deep concern and all of us agreed (they) ... were fundamentally negative and a step backward," he told the AP. "So now the task for us is to agree on a way forward."

Burns reiterated that the United States expected action in the Security Council after an April 28 deadline for Iran to stop uranium enrichment.

He gave no specifics as to the type or timing of sanctions and he refused to say whether Russia had softened its opposition to sanctions against Iran.